The coalition of groups that backs Prop. 8, California's ban on gay marriage, has asked all the judges of the Ninth Circuit to rehear the case decided by a three-judge panel on Feb. 7. An appeal to the US Supreme Court could still follow.

Same-sex wedding cake toppers are seen outside the East Los Angeles County Recorder's Office on Valentine's Day during a news event for National Freedom to Marry Week in Los Angeles. Backers of the California ban on gay marriage, Proposition 8, announced their next step Tuesday.

WASHINGTON — Supporters of a ban on same-sex marriage in California on Tuesday asked the full federal court of appeals court in San Francisco to reconsider a ruling by a divided three-judge panel that struck down the controversial law.

Lawyers for Protect Marriage, a coalition of groups supporting the Proposition 8 ballot initiative, filed a 52-page petition asking the Ninth US Circuit Court of Appeals to reverse the panel’s ruling.

“The panel majority’s decision conflicts with decisions of the United States Supreme Court and this Court, and consideration by the [full appeals] court is therefore necessary to secure and maintain uniformity of the court’s decisions,” wrote lead counsel Charles Cooper.

A three-judge panel of the Ninth Circuit ruled 2 to 1 on Feb. 7 that the ballot initiative and related state constitutional amendment violated the civil rights of gay and lesbian couples seeking to marry.

The appeals court had been asked to rule on whether same-sex couples enjoy a right under the US Constitution to marry on equal terms as heterosexual couples.

The panel declined to address that issue and instead invalidated the measure under a different line of analysis, relying on a Supreme Court decision that prohibited states from singling out homosexual citizens for disfavored and unequal treatment.

The Prop. 8 lawyers had two weeks to decide whether to allow the decision to stand unchallenged or to appeal it. They could take the case directly to the US Supreme Court or ask a larger group of Ninth Circuit judges to rehear the case. Such a proceeding is called en banc review.

The petition does not discuss or hint at the lawyer’s litigation strategy and why it might be better to allow a larger number of appeals court judges to mull the issues before potentially taking the high profile, highly controversial case to the Supreme Court.

Mr. Cooper’s basic argument in the petition is that the appeals court panel was wrong and is in need of correction.

“It is hardly surprising that every state and federal appellate court decision, including binding decisions of the Supreme Court and this Court, to address the validity of traditional opposite-sex marriage laws under the federal Constitution has upheld them as rationally related to the state’s interest in responsible procreation and child-rearing,” Cooper wrote.

“The panel majority erred in breaking with the uniform and binding precedent upholding the constitutionality of laws adopting the traditional definition of marriage, and the Court, sitting en banc, should rehear this profoundly important case,” he said.